We review recent advances in the generation of polarization-tailored ultrashort bichromatic laser fields and their application to the coherent control of ultrafast photoionization dynamics. In the experiments, we use polarization-shaped bichromatic laser pulses to control three-dimensional photoelectron momentum distributions from atomic multiphoton ionization. To analyze the underlying physical mechanisms, we consider two bichromatic control schemes based on high-order intrapulse frequency mixing and interband N₁- vs. N₂-photon interference, respectively. In the first scheme, interferometric (ω:2ω) fields are used to select or suppress specific ionization channels in the resonance-enhanced 2-photon ionization of potassium atoms by second-order intrapulse frequency mixing. In the second scheme, we utilize a white light polarization pulse shaper to generate carrier-envelope phase-stable (3ω:4ω) fields in order to manipulate the symmetry properties of photoelectron wave packets from 3- vs. 4-photon ionization of sodium atoms. In both cases, bichromatic polarization control of free electron wave packets is based on the creation of a superposition of multiple angular momentum states with different kinetic energy spectra. We discuss the vorticity of these mixed angular momentum states and show that the kinetic energy spectra are determined by the bichromatic multiphoton spectra, emphasizing the close relationship between bichromatic multiphoton ionization and nonlinear optical spectroscopy.

我们回顾了极化定制的超短双色激光场及其在超快光电离动力学的相干控制中的应用的最新进展。在实验中，我们使用偏振形状的双色激光脉冲控制来自原子多光子电离的三维光电子动量分布。为了分析潜在的物理机制，我们考虑了两种分别基于高阶脉冲内频率混合和带间N ₁ - N _2-光子干扰的双色控制方案。在第一种方案中，干涉法（ω：2ω场用于通过二阶脉冲内频率混合来选择或抑制钾原子共振增强的2-光子电离中的特定电离通道。在第二种方案中，我们利用白光偏振脉冲整形器生成载波包络相位稳定（3ω：4ω）场，以操纵钠原子的3-与4-光子电离引起的光电子波包的对称特性。在这两种情况下，自由电子波包的双色偏振控制都基于具有不同动能谱的多个角动量态的叠加。我们讨论了这些混合角动量态的涡度，并表明动能谱由双色多光子光谱确定，强调了双色多光子电离与非线性光谱之间的密切关系。